Algae microrobots could aid the effort to control tumour cells

[China] Jiao Niandong works with creatures visible only through a microscope. His building blocks at Shenyang’s Institute of Automation are green algae that one day may assemble new materials, treat water pollution or fight cancer.

Your research paper on the algae experiment was recently the cover article in the scientific journal Lab on a Chip published by Britain’s Royal Society of Chemistry and is drawing attention. What can you tell us about the experiment?

We found a way to control algae’s movement in water. We built a device to demonstrate its feasibility. The device has a sandwich structure, with the top and bottom layers being glasses coated by light-sensitive films, and the middle a cell platform containing living colonies of algae in fluid.

Jiao Niandong

We directed light beams on the films. The films converted the energy of photons (particles of light) to electricity, and the electric fields generated a hydraulic force in the water of the cell platform. We used the hydraulic force to confine, direct and manipulate movement of algae cells. They took orders from humans and behaved well as microrobots.

This is the first time that live algae cells have been trapped and formed into a micrometre-sized motor array. Why algae?

From an engineer’s point of view, each alga is a microrobot. It can feel the environment and move around. It absorbs energy from the surroundings and converts chemical power to mechanical drive.

Algae are also fast swimmers. In the experiment, we used a common species called Chlamydomonas reinhardtii, which was about 10 micrometres in size but could swim a distance more than 10 times its body length in a second. In our bigger world, that speed was equivalent to a car running 180 kilometres per hour.

The microscopic world is full of chaos. If we can command algae, we can control and manipulate the movements of other small microorganisms or substances such as bacteria, red blood cells and tumour cells. We can bring order into the small world.

How does the alga swim?

An alga has a pair of lash-like antennas known as flagellums. It moves constantly by paddling the flagellums in water like a swimmer swinging a pair of very long arms. But the movement is spontaneous, the direction aimless.

How to confine and control algae’s movement has challenged researchers for many years.

Conventional techniques such as trapping with mechanical, acoustic, electrostatic and magnetic forces were only used to capture lifeless particles and non-swimming cells. Some researchers proposed [using] laser, but the high energy of a laser beam could injure or kill the algae. Our method did not require a direct physical contact to the algae, and the light we used is gentle, harmless.

How did the algae respond to your command?

We made them stay within a circular fence of light, like keeping cattle in a range. We moved them from one place to another by moving a light beam. When the beam stops, they swim around the light dot. The speed of the rotation changed as we changed the intensity of light.

What’s the use of turning algae into microrobots?

Microrobots can move and carry cargo at the micro scale. If a microorganism can travel in a straight line, or any course designated, it can become an efficient transporter for various purposes, such as drug delivery. [Microrobots] can also work as construction workers to build complex structures such as bioactuator and biological chips.

When an alga rotates, as we demonstrated in the experiment, it becomes a motor. When many colonies of algae rotate together, they make a powerful array of motors. The rotation, if coordinated and laid out well, would be able to stimulate fluid flow and generate power for other mechanical devices.

There is a concern that robots can increase the unemployment rate by taking away many jobs. With the help of artificial intelligence, will robots replace humans one day?

A microrobot will not acquire intelligence. Its size is too small, with no room for a sophisticated computer chip. If they join our work force in the future, they will be simple-minded workers who deal with certain delicate tasks. They are not competitors to humans, but only a new, powerful tool to be put into human hands.

Even bigger robots will not become a threat to humans, in my opinion. I understand that the recent advancement of artificial intelligence technology, such as Google’s board game machine, AlphaGo, made many people worried. The best way to ease the panic is to visit a robotic research facility and see how robots work. You will see that they are still calculating, not thinking. They don’t have emotions or inspirations. They are programmed.

A tool may sometimes harm its master, but it will never become the master itself.

What does your laboratory look like?

We are venturing into unchartered territory, with many things waiting for our discovery. To survive and thrive in this area, you’ve got to be creative. So our micro/nano lab is an interdisciplinary laboratory with researchers from many different disciplines working together. We are a mechanical and electronic engineering lab. We put different technologies together to see how they work under a microscope. We are a biological lab, with many culture dishes to grow various types of microorganisms. We are also a material science lab, developing and experimenting with fancy materials, such as graphene, to find out their use in nanodevices.

In this kind of multi-disciplinary environment, exciting ideas and discoveries sometimes came up like popcorn.

What is the biggest challenge for a micro/nano robotics scientist?

Patience. Sometimes we need to sit in front of a microscope for days to observe a single phenomenon, which is a challenge to [both] eyesight and will.

How strong is China’s micro/nano robot research, compared with the West?

Neck and neck.


View original article at: Making green algae circle a dot of light could aid the effort to control tumour cells





Leave a Reply